In U.S. Pat. No. 4,998,900, and the corresponding international patent no PCT/CA91/00218 (publication no WO-91/19642), there is described and illustrated a self-righting inflatable life raft having upwardly and outwardly extending inflatable tubes. These tubes are arranged to cause the life raft to be unstable if inverted. In particular, the center of gravity of the life raft if inverted will be outside of the bottom of the life raft so that it will by gravity topple back to the upright position. The complete disclosures of the US and international patent specifications are incorporated herein by reference so that the disclosures thereof are to be read as part of this specification and the present invention is to be understood and construed in the context of those disclosures of prior art.
If the inflatable tubes in these prior constructions do not inflate or, after inflation, are subsequently collapsed or distorted, they may not adopt their desired positions extending upwardly and outwardly from the side walls of the main body, sufficient to make the life raft topple to the upright position.